Chapters 5 and 6: Electron Configurations and Periodic Trends

Vocabulary flashcards covering atomic structure, electron configurations, orbital types, element classifications, and periodic trends from Chapters 5 and 6.

Shell

The concentric circular orbits that electrons are confined to within an atom.

Subshell

A section of an electron shell ($s$, $p$, $d$, or $f$) divided into orbitals, with each specific subshell holding a characteristic number of orbitals.

Orbital

A region of space centered around the nucleus of an atom in which electrons are found most of the time; each individual orbital can hold up to $2$ electrons.

Aufbau Principle

The principle stating that electrons fill orbitals from the bottom up, occupying the lowest possible energy level first.

Hund's Rule

The rule stating that electrons repel each other and spread out as far as possible, occupying empty orbitals within a subshell singly before pairing up.

Diamagnetic

Describes atoms that have no unpaired electrons, resulting in a very weak response to a magnetic field.

Paramagnetic

Describes atoms that have unpaired electrons, resulting in a stronger response to a magnetic field.

Condensed Form AKA Noble Gas Form

A shorthand electron configuration notation where the symbol of a Group 18 noble gas whose configuration matches the inner core electrons is enclosed in brackets, followed by the remaining outer configuration.

Electron Configuration Exceptions (Cu and Cr)

The stability exception in copper and chromium where an electron is taken from the $4s$ subshell to fill or half-fill the $3d$ subshell.

Ground State

The lowest possible energy state of an atom where electrons follow normal configuration rules and occupy the lowest available energy levels.

Excited State

The state resulting when electrons absorb energy from an external source (heat, electricity, or light) and are promoted to higher energy levels, leaving lower energy subshells unfilled.

S Orbital

A spherical orbital found in the $s$ subshell, with $1$ orbital per energy level.

P Orbital

A peanut-shaped or dumbbell-shaped orbital found in the $p$ subshell, with $3$ orbitals per energy level.

D Orbital

A daisy-shaped or four-leaf clover-shaped orbital found in the $d$ subshell, with $5$ orbitals per energy level.

Metals

Elements on the left side of the periodic table staircase (excluding $H$ and $Mt$) characterized by malleability, ductility, luster, high electrical and thermal conductivity, high density, and high melting points.

Nonmetals

Elements on the upper right area of the staircase (including hydrogen) that are brittle, dull, poor conductors of heat and electricity, and have low densities and melting points.

Metalloids

Elements along the staircase ($Ge$, $Sb$, $B$, $Si$, $As$, $Te$, $At$) that exhibit properties of both metals and nonmetals.

Alkali Metals

The metallic elements located in Group 1 of the periodic table.

Alkaline Earth Metals

The metallic elements located in Group 2 of the periodic table.

Transition Metals

The elements situated in Groups 3 through 12 of the periodic table.

Inner Transition Metals

Also called rare earth metals; the $f$-block elements consisting of the Lanthanides ($4f$ block) and Actinides ($5f$ block).

Halogens

The highly reactive nonmetal elements located in Group 17 of the periodic table.

Noble Gases

The elements located in Group 18 of the periodic table used as bracketed cores in condensed configurations.

Effective Nuclear Charge ($Z_{eff}$)

The net positive charge that an electron feels from the nucleus, calculated as $Z_{eff} = Z - S$, which increases from left to right across a period and remains constant down a group.

Valence Shell

The outermost electron shell of an atom that interacts with the outside environment and governs the atom's chemical properties.

Core Electrons

Inner electrons (shielding electrons), represented by $S$, that cancel out the positive charge of protons felt by valence electrons.

Atomic Radius

The distance from the nucleus to the valence electrons (measured in Angstroms), which increases down a group, decreases from left to right, and peaks in the bottom left corner of the periodic table.

Ionization Energy

The amount of energy required to remove a valence electron from an atom, which decreases from top to bottom, increases from left to right, and peaks in the top right corner of the periodic table.

Reactivity

The tendency of an element to react faster and more aggressively at cooler temperatures and lower concentrations, driven by electron loss in metals (low $Z_{eff}$, large radii) and electron gain in nonmetals (high $Z_{eff}$, small radii).